That whining could be from your PSU or the motherboard's VRM's. Post your system specs. 

Ehh, not such a big fan of Paidmax PSU's, have heard a lot don't put out the right wattage they advertise, how old is the PSU?

If I were you, I'd def. have the system run on full load, maybe EVGA OC scanner for just the GPU and open the side panel door and keenly listen near the GPU or the PSU. You should be able to distinguish which component it's coming from by just listening. It really could be the PSU is going bad because a GTX 460 would not whine unless it's been folding under a blanket for the entire year baking in heat, lol. Your probably hearing a capacitor straining under heavy load while gaming. 

Try then doing a CPU load on the system using like Prime95 or OCCT to load only the CPU, if you hear the whine, it's the PSU, if not then it's the video card for sure.

The fans on EE models whine terribly at speeds above 60-65%, play with the fan speed while not stressing GPU, just manually change it.  See if you can make it come and go at will.

if it's a high pitched kind of squeal coming from the graphics card, then it is just capacitor whine, nothing to worry about.
 
A way to test to see if it is , is to load up oc scanner and load the card, then change the core frequency of the graphics card. if the sound changes - lower when you lower the overclock and higher when you increase the overclock, then it is definitely the capacitors on the graphics card.
Over time, sometimes the noise will reduce.
 
That power supply may well be an issue, it's getting a bit old, and was never a good one to begin with.  I'd suggest your next purchase/upgrade be a new power supply.  With those specs you don't need anything huge. A good 650w would be fine for your system.  Maybe an 800 if you plan on upgrading your graphics to sli or 480/580 in the future.
 

it will decrease life a little bit, but there is no way to tell how much.
it's better to increase the core speed and leave the memory alone.
 
As for the whine, it's what capacitors do. sometimes it's audible, sometimes not.
 

I'd say start an RMA, I've heard a lot of 460's with capacitor whine is not a good thing.